We propose a multidisciplinary study of the pathophysiology of lung fluid and solute exchange, using techniques of anatomy (gross, microscopic and ultrastructure), autoradiography, hematology, physiology, meurology, surgery, pediatrics (fetal physiology) and clinical investigation. Studies in animals (A projects) will be directed at the examination of fluid and protein exchange across the microvascular endothelial and alveolar epithelial barriers in fetal, newborn and adult sheep and in adult dogs under a wide variety of edemogenic conditions. Dr. Staub and associates (A-1) will study the role of formed blood elements (emphasis on neutrophils) and the coagulation cascade in microembolic lung injury. Dr. Staub and associates (A-2) will investigate the role of the alveolar barrier in the formation and clearance of airspace flooding. Dr. Staub and associates (A-3) will test basic assumptions about tissue fluid and lymph protein concentration in the lung. Dr. Bland (A-4) will study perinatal factors affecting lung fluid and protein balance. Dr. Lewis (A-5) will investigate the time course and mitigating events in septic lung injury. Dr. Simon (A-6) will determine the specific event, site of action and pathways relating to neurogenic pulmonary edema. Dr. Bhattacharya (A-7) will make direct measurements of lung surface microvascular and perimicrovascular pressures to quantify the forces governing fluid balance. Investigations in a cross disciplinary human patient papulation (B project) will determine the natural history, risk factors, treatment and specific pathogenesis of lung injury and edema. Interrelations to animal studies will be emphasized.